Plant Nucleotide Metabolism. Hiroshi Ashihara
AR, Adenosine; ATP, adenosine triphosphate. Cytokinin ribosides: DHZR, dihydrozeatin riboside; iPR, isopentenyladenosine; tZR, trans-zeatin riboside. IR, Inosine; GR, guanosine; XR, xanthosine; AdR, deoxyadenosine; GdR, deoxyguanosine.
a) Native enzyme.
b) Recombinant enzyme.
c) Activity was detected but no data was published on the Km value.
Almost homogeneous AK was isolated from seeds of yellow lupin (Lupinus luteus) by Guranowski (1979b). The Km value for adenosine was low (1.5 μM), but was higher (300 μM) for ATP. This trend is also found with AK from other plant sources (Table 5.3). ATP is the main phosphate donor. dATP and guanosine